This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:    CM cubic metric    CoMP coordinated multipoint    DL downlink    DTX discontinuous transmission    DSR dynamic spectrum refarming    eNodeB evolved node B or E-UTRA nodeB    FDD frequency division duplex    GSM global system for mobile communications    HSPA high-speed downlink packet access    IMT international mobile communications    IR invention report    LTE long term evolution    PRB physical resource block    TDD time division duplex    TDMA time division multiple access    TX transmitter    RAT radio access technology    RNC radio network controller    RX receiver    RRS reconfigurable radio system    SCC secondary component carrier    TDD time division duplex    UE user equipment    UL uplink    WLAN wireless local area network
A GSM system is a narrow-band communication system, a bandwidth of which is about 200 kHz. When GSM systems are used to form a cellular network, different frequency points can be used between possibly interfering neighbor cells, so as to avoid co-channel interference. Usually interference from another system, which is not detected by a primary system, may typically be assumed to be white Gaussian noise from own signal point of view. This can be the assumption when different radio technologies cause interference towards each other, for example GSM and LTE. This may be assumed only if there is high enough correlation between used reference symbols (e.g. channel estimation symbols for data or similar critical symbols) and reference symbols used by other radio system. With only these assumptions primary system scheduling itself cannot use directly interference symbols to optimize allocation. Further, only simple averaging of interference levels may be used in such cases for taking account other system interference. However, averaging interference level scheduling is seen to not be optimal.
In addition, averaging interference levels is also used for other system interference or it is expected that there does not exist co-channel interference due to for example system configuration or frequency planning of system. Still another practiced method is to use some filtering of interference to optimize interference level measurement. Disadvantages include that averaging or filtering can't be used for identification of fast and random time domain changes, and this way benefit from those changes, e.g. in case of GSM system. The exemplary embodiments of the invention address at least these and related shortfalls.